Heretofore, as a method for cleaning a semiconductor wafer such as a silicon wafer, a cleaning method called RCA cleaning using a SC-1 (Standard Cleaning 1) solution and a SC-2 (Standard Cleaning 2) solution has been widely employed. The SC-1 solution is an aqueous solution of ammonium hydroxide and hydrogen peroxide, and is characterized by quite excellent performance of removing particles on the semiconductor wafer surface. The SC-2 solution is an aqueous solution of hydrochloric acid and hydrogen peroxide, and plays a role in removing metal impurities.
For example, Patent Literature 1 describes a method for cleaning a semiconductor wafer by using an SC-1 solution and an SC-2 solution to prevent anions from adhering to the semiconductor wafer surface when the SC-2 solution is used in cleaning (SC-2 cleaning). In the method, the SC-1 solution is used in cleaning (SC-1 cleaning) in such a manner that a cationized metal remains on the surface of the semiconductor wafer.